Low-level ID3v2 access from the audio tag overlay. For everyday title/artist/album values prefer Audio Tag tokens.
Reads one supported ID3v2 frame by four-character frame id (for example TALB,
TIT2, TXXX).
Signature: <id3v2:field-code> or
<id3v2:field-code:content-descriptor>
<id3v2:TXXX> returns the first TXXX frame.
Add a content descriptor to target a specific frame:
<id3v2:TXXX:catalog>.
COMM / USLT, bare ids use the primary instance; an optional
content-descriptor suffix selects another instance.
Example: <id3v2:TIT2>
ID3v2 tag version text (for example 2.3 / 2.4), or empty when no ID3v2 tag is present.
Signature: <id3v2-version>